Royal e



(No Model.)

R. E. BALL. v CARBON FOR ELECTRIC ARO LAMPS. I

No. 506,459. Patented O t. 10,1895.

UNITED STATES PATENT OFFICE.

ROYAL E. BALL, on NEW YORK, N. Y.

CARBON FOR ELECTRIC-ARC LAMPS.

SPECIFICATION forming part of Letters Patent No. 506,459, dated October10, 1893.

Application filed April 28, 1892.

To an whom it may concern.-

Be it known that I, ROYAL E. BALL, a citizen of the United States,residing at New York city, county and State of New York, have inventedcertain new and useful Improvements in Garbons for Electric-Arc Lamps,of which the following is such a full, clear, and exact description aswill enable any one skilled in the art to which it appertains to makeand use the same, reference being had to the accompanying drawings,forming part of this specification.

My invention relates to carbons for electric arc lamps and the object ofthe invention is to increase the life or burning capacity of the lamp.

There is at present a demand for some device, simple and, if possible,without mechanism, that can be attached to ordinary single arc lamps nowin use and which willburn for twelve or sixteen hours. Oarbons oflargerthan ordinary diameter will do this, but the great drawbacks to them arethat they consume much time in pointing themselves and heating up andthat during such time which is the time when the best light is needed,the light is not good or at its best.

I overcome these objections by my invention which consists in a carbonof gradually diminishing thickness or diameter from its butt end to itsarc-forming end.

I have illustrated a type of my invention in the accompanying drawings,wherein two tapered or conically-shaped carbons, A and B, respectively,are shown as detached and arranged in axial alignment in the usualmanner, to form the arcing space. The longer carbon, A, constitutes themovable or uppercarbon which is fed to the are as the carbons waste awayand B is the lower carbon. Both of these carbons are coned or taperedfrom their butt ends c, to their arc-forming ends (1, thus graduallydiminishing in diameter or thickness throughout their length. Of coursethe taper of the carbon need not I extend the entire length thereof, ifpreferred,

Serial No. 430,944- (No model.)

but the carbon should be tapered almost its entire length or at leastthroughout the length that is to be burned. Though the type of thecarbon shown is conical in form, this form need not necessarily beadhered to, for other forms differing in cross-sectional shape may beusedthe gradually diminishing thickness or diameter is, however, to bepreserved.

I find that good practical results can be obtained by the use of acarbon about twelve inches long, seven-sixteenths of an inch in diameterat the point or arc-forming end and seven-eighths of an inch at the buttend.

By making the carbons of a gradually diminishing diameter or thickness,the light is started with carbon points of the size of most advantageand these points burn as fast nearly as ordinary carbons. In the latterhours of the life of the carbons-the hours of least importance in nightservice-the slowburning or larger part of the carbons, which have,however, become properly pointed and heated up during the earlier partof the run or life of the carbons are then consumed.

Having thus described my improvementsin carbons for electric-arc lamps,what I claim as my invention, and desire to secure by Letters Patent,is-

' 1. In an arc-lamp, the combination of a pair of carbon pencilsarranged end to end in axial alignment and one or both of the samegradually diminishing in diameter or thickness from or near the. buttend to the areforming end thereof. 2. A cone-shaped carbon forarc-lamps.

3. A conically-shaped carbon for an electric arc lamp. 7

In testimony whereof I have hereunto set my hand this 18th day of April,1892, in the presence of the two subscribing witnesses.

ROYAL E. BALL.

Witnesses:

G. D. SoWEEs, E. E. FRENCH.

